Cyclopentadiene, cyclopentene and cyclopentane and alkylated derivatives thereof are known in the art. Further, methods are known for preparation of alkylated cyclopentadienes and conversion of these materials to cyclopentenes and cyclopentanes. There is substantial interest in cyclopentadienes, cyclopentenes, and cyclopentanes since cyclopentadiene is characterized by the unique property of being the most acidic aliphatic hydrocarbon known, having a pKa of 18, and also because its reactions as a Diels-Alder diene are extremely facile. Because of the aromaticity of the cyclopentadiene anion (c--C.sub.5 H.sub.5.sup.-), cyclopentadiene is easily the most acidic of the simple hydrocarbons and in fact is comparable in acidity to alcohols. This means that substantial amounts of the anion can be generated with alkoxides and even concentrated solutions of hydroxide. Since it is uniquely stable, it can participate in the carbanion reactions of alkylation, acylation, carboxylation and the like.
U.S. Pat. No. 3,255,267 to Fritz et al discloses the alkylation of cyclopentadiene and monoalkylcyclopentadiene with a single primary or secondary alcohol in the presence of a highly alkaline catalyst, including the disclosure of trialkylated and tetralkylated products. Fritz et al do not appear to contemplate using mixed alcohols for alkylation and the alkylcyclopentadiene products disclosed cannot have more than two different alkyl groups, a single substituent derived from starting cyclopentadiene and the rest derived from the alcohol.
The cyclopentadienes described by Fritz et al contain primary hydrocarbon substituents of up to 11 carbon atoms and secondary hydrocarbons of structure R.sub.c R.sub.d CH, where R.sub.c is selected from "hydrocarbon radicals free of aliphatic unsaturation, including alkyl and aryl radicals, said radicals having from 1 to 10 carbon atoms;" and R.sub.d is "a hydrocarbon radical free of aliphatic unsaturation, including alkyl and aryl radicals, said radicals having from 1 to 10 carbon atoms,". An additional class includes R.sub.c R.sub.d =--CH.sub.2 (CH.sub.2).sub.n CH.sub.2 -- where n is an integer having a value of 1 to 10. Thus, Fritz et al teach compositions in which no more than two different kinds of hydrocarbyl groups may be present, and in which no more than one hydrocarbyl group may occur more than once. Thus, the products which can be produced by Fritz et al are controlled by this disclosed alkylation reaction which uses only a single alcohol. In addition, Fritz et al teach that "Ethanol is by far the preferred primary alcohol since the yields obtained with this alcohol are much in excess of the yields obtained when employing other primary alcohols." Fritz et al present two examples of alkylation with primary alcohols with the following yields based on cyclopentadiene:
Example 24: Ethanol plus cyclopentadiene--17.8% yield
Example 26: 2-Ethylbutanol plus cyclopentadiene--1.6% yield.
Applicants have discovered that the process improvement of removing water from the reaction as it is formed greatly increases the yields obtained with primary alcohols to near quantitative levels and that using mixtures of alcohols provides an alkylation reaction which produces a wide variety of novel and useful alkylated cyclopentadienes.
U.S. Pat. No. 3,560,583 discloses cyclopentadiene compounds containing up to five substituents, which substituents can be independently hydrogen, alkyl, aryl or aralkyl. These compounds are prepared by reaction of a cyclopentadiene compound with benzyl halide or allyl halide, an alkali metal hydroxide and a quaternary ammonium salt catalyst.
Polish patent No. 55,535 to Makosza, 1968, discloses indene compounds which contain alkyl substituents on the cyclopentadiene portion of the molecule. However, the working examples indicate that only a single alkyl group or two allyl groups are present. U.S. Pat. No. 3,931,334 discloses lubricant compositions which comprise substituted indans, the indan molecule being substituted by methyl and styryl.
In a thesis by Stephen S. Hirsch, University of Maryland, 1963, there is disclosure of base catalyzed alkylation of cyclopentadienes utilizing alcohols to effect the alkylation. Included in this disclosure are alkylation reactions with benzyl alcohol to produce cyclopentadienes which can contain as many as five benzyl substituents. Also disclosed are 1,3-dialkyl indenes.
Polish patent No. 55,571 to Makosza discloses cyclopentadienes and processes for preparation of monosubstituted cyclopentadienes by the use of phase-transfer alkylation. The patent is limited to monosubstituted compounds with short chain alkyl groups.
The prior art contains numerous disclosures of methods for the preparation of substituted cyclopentadienes but wherein the substituents usually are short chain alkyl groups. The methods of preparation of such materials vary but do include such processes as the reaction of the cyclopentadiene with alkyl halides in the presence of a base as in U.S. Pat. No. 2,953,607. Similar disclosures may be found in U.S. Pat. Nos. 3,131,227, 4,547,603, 4,567,308, 3,560,583, 4,412,088, and 3,755,492. Of particular interest is 3,131,227 which discloses polysubstituted cyclopentadienes such as pentamethyl and hexamethyl cyclopentadiene which is prepared by a cyclization reaction. Also in U.S. Pat. No. 4,567,308, alkyl cyclopentadienes and alkylated derivatives thereof are prepared by the vapor phase reaction of a cyclopentadiene derivative and an aliphatic lower alcohol in the presence of a basic catalyst. These cyclopentadienes and alkylated products are disclosed as being additives for synthetic rubbers, starting materials for resins and/or industrial chemicals.
In a publication by J. Denis, Journal of Synthetic Lubrication, Vol. 1, p. 201-219 (1985), there is disclosure of hydrocarbons which may be used in lubricant compositions. Specifically mentioned in this publication are cycloalkanes and in particular monoalkyl substituted cyclopentanes. This publication in a comparison of various hydrocarbon structures including normal alkanes, alkanes branched by one or more alkyl chains or by a ring, cycloalkanes and aromatics as base stocks for lubricants.
In a publication by Rong et al, Acta Chemica Sinica, Vol. 41, No. 10, Oct., 1983, there is disclosure of the use of polyethylene glycol as a phase transfer agent for halide alkylation of cyclopentadiene with alkyl halides. The products produced are monoalkyl substituted cyclopentadienes. In a related article by Rong et al, Journal of Chinese Universities, Vol. 4, page 576-580 (1983), there is disclosure of the synthesis of alkyl substituted derivatives of cyclopentadiene by the phase transfer catalytic reaction of cyclopentadiene with alkyl halides in the presence of potassium hydroxide and polyoxyethylene surfactants as a catalyst. Only monoalkyl substituted cyclopentadienes are prepared.
U.S. Pat. Nos. 3,004,384, 3,356,704, 3,358,008, 3,388,180, 3,391,209, 3,414,626, and 3,419,622 disclose polysubstituted cyclopentadienes and cyclopentanes but wherein the substituent is a short chain alkyl group or allyl group. Finally, U.S. Pat. Nos. 3,751,500 and 3,636,176 disclose indene compounds which can contain short chain alkyl substituents which are useful as perfume compositions.
In none of the prior art of which Applicants are aware are there disclosures of poly-hydrocarbyl cyclopentanes, cyclopentadienes, cyclopentenes, and mixtures thereof which are useful as lubricant compositions, which useful products may be prepared from novel hydrocarbyl-substituted cyclopentadienes. The present invention provides such novel products as well as methods for their preparation and methods for their use.